Unusual flaw on boolits from a Lee mold

[David2011]

I cast some Lee 357-158 flat nose boolits over the weekend and had a curious problem. The mold is a recent 6 cavity one with the enhanced vent lines. Unfortunately I can't post pictures for a couple of days. The boolits were lightly frosted and the alloy was 50/50 coww/Linotype. Yes, it's a waste of Lino IMO but my friend provides the metal for his boolits and that's what he likes.

A lot of the boolits had a circular flaw on or near the parting line on the side of the boolits near the base. The rejection rate was probably 70%. It was not in exactly the same place on any of them, eliminating defects in the cavities as the source. The noses were wrinkle free and I use a hot plate so pretty sure the mold was hot enough. I'm wondering if my pouring technique is at fault. I hold the mold at a slight angle with the handle lower than the hot end so the puddle moves toward the cavity that was poured last. I'm also wondering if the alloy might not br wetting out properly but I cast about 250 more from the same pot of alloy using a 2 cavity RCBS 9mm TC mold and the only rejects were the first and second pours. The next 250 were perfect.

I'll post pictures as soon as I get home, probably tomorrow.

192708 192709 192707

Solution found: Plugged vent line. Not temperature related as it might first appear.

David

[bobthenailer]

Mould fill out ! rounded corners

[popper]

Venting and pour problem. Pour straight into the mould, change pour rate. Break the top of the mould edges with a stone or something - just enough to know it's there.

[runfiverun]

venting.
you can either add some to the edges of the cavity's [run a sharpening stone down them to break the edge slightly] or pour slower to let the air out of the sprue hole.

[Rattlesnake Charlie]

Since the reject rate went away after the second or third pour, I don't think the mold is the problem. Learn what that mold likes, and feed it accordingly. Most likely the mold was too cold when starting to pour a new batch from the pot.

[Wayne Smith]

Since the reject rate went away after the second or third pour, I don't think the mold is the problem. Learn what that mold likes, and feed it accordingly. Most likely the mold was too cold when starting to pour a new batch from the pot.

No, that was a different mold.

Are you talking about a visual color difference or a lack of alloy in these spots?

[runfiverun]

I bet it's a little depressed swirl with a loop like feature to it on the side of the boolit near the vent line.
I'm working on an MP mold right now that does this.
I know it's venting because I can make it not do it and I can make it do it at will.

[David2011]

I bet it's a little depressed swirl with a loop like feature to it on the side of the boolit near the vent line.
I'm working on an MP mold right now that does this.
I know it's venting because I can make it not do it and I can make it do it at will.

Bingo! I just need to know what I'm doing that causes it. Back at home with a new knee and posted pictures. As you can see, all of the corners are quite sharp. I do believe the mold it up to temp. I'm not new to casting; just a new-to-me problem. All of the abberations are on the sides of the boolits; not rounded bases. The vent lines in this mold are fly-cut, deep grooves; not at all like older Lee fine line vents. Exercise/torture time. Be back later.

[gwpercle]

Try pouring straight down into the hole with mould held level and also try placing sprue hole against the pot nozzle as in pressure casting and if that doesn't work , try leaving just a tiny air gap between sprue hole and nozzle with all level . You never know how a mould likes to be operated, but the tilting of the mould may be the culprit .

Get well soon,
Gary

[David2011]

Gary,

Thanks for the well wishes. Casting will be one of the first activities I'll be able to resume. I played with flat/fwd tilt/aft tilt when observing the problem. Tilting away from the handles was the expected failure since very hot melt ran toward the next hole to be filled. will try pressure casting with this mold but expect the results to look like latticework. Will definitely have to take pix.

David

[runfiverun]

you just need to let the air out of the cavity as the alloy is going in.
I control it with pour speed when I use the mold.
but will break the edges of the mold here shortly since I'm setting it up for an automated machine for someone else.

[mold maker]

Even a slight change in the delivery of melt to each cavity can cause the effect. On a multi-cavity mold the movement from one cavity to the next can cause an interrupted flow so that a too cool mold has melt flowing over already cooled lead. This is a layering effect that is solved by a hotter mold and attention to mold movement, timed with the overflow of melt.
I think you solved your own problem, as only the first pours exhibited the phenomenon.

[David2011]

Even a slight change in the delivery of melt to each cavity can cause the effect. On a multi-cavity mold the movement from one cavity to the next can cause an interrupted flow so that a too cool mold has melt flowing over already cooled lead. This is a layering effect that is solved by a hotter mold and attention to mold movement, timed with the overflow of melt.
I think you solved your own problem, as only the first pours exhibited the phenomenon.

No, the problem existed for as long as I used the Lee mold. The 9mm Lyman using the same alloy made perfect boolits as did an RCBS in .45 cal. If you look at the driving bands and bases they're well filled out indicating that the mold is not cool. The boolits are all slightly frosty, again indicating a fairly hot mold. I've been casting for 35 years so I think I have a good feel for being consistent.

I'll try again with a more standard alloy as soon as I'm able to walk to the shop again.

[JSnover]

I started out pouring straight into the hole but had the same problems. Now I either pressure cast or let the stream hit a little off-center so it swirls down into the cavity. Good results either way for me.

[tomme boy]

Had the same thing happen to a Accurate mold. Then one day it went away. Never did figure it out. I figured it was teflon was in with the oil Tom used to cut the mold. It took 6 cleanings with brake cleaner and casting sessions before it went away.

[matrixcs]

Another idea/tip is to make sure there is adequate metal on top of the sprue plate. It helps keep the metal hot at the top of the fill allowing for better top (base of bullet) fill out.

[Sasquatch-1]

Before messing with the mold, try adding a little tin to the mix in the form of pewter or solder.

[OS OK]

Clean the heck out of the mold...it is gassing from a foreign substance (prolly lube) in the pores/grain of the metal of the cavity.

[mozeppa]

take off one sock ...switch pockets with your keys and wallet....put your hat on backwards (forwards if you wear it backwards normally.)

then try again.:wink:

[243winxb]

Clean the heck out of the mold...it is gassing from a foreign substance (prolly lube) in the pores/grain of the metal of the cavity. I will buy this quote, but dont know, dont use aluminum Lee moulds. Dirty alloy and cold, needing a faster pour. I i been casting for 50 years. :D

[David2011]

Just had an opportunity to mess with this a little more. Maybe a little was learned. The original alloy was 20 pounds of 50/50 COWW and Linotype. That should have had 2.25% tin, 7.5% antimony, .13% arsenic and 90.1% lead. When I had the problem with teh circles on the sides of the boolits I added about 4 ounces of pewter. That bumped the tin to about 3.46% and lowered the other percentages only slightly.

It's now 25% COWW, 25% and 50% lead. That should be 1.74% tin, 3.73% antimony, 0.06% arsenic and 94.5% lead. Some of the last session and all of today's tests were done with this alloy.


Another idea/tip is to make sure there is adequate metal on top of the sprue plate. It helps keep the metal hot at the top of the fill allowing for better top (base of bullet) fill out.

Yes, I pile up as much on top of the sprue plate as I can to provide the pressure and extra alloy to fill in as the boolit cools.


Before messing with the mold, try adding a little tin to the mix in the form of pewter or solder.

That was the first thing I tried other than temperature changes. I added straight pewter; couldn't tell any difference


I will buy this quote, but dont know, dont use aluminum Lee moulds. Dirty alloy and cold, needing a faster pour. I i been casting for 50 years. :D

. . . and this is why I use Lee molds as little as possible. Smaller cavities are more difficult for me to get to work than larger ones. The alloy casts fine in other molds, right out of the same pot. I tried 2 other molds, neither of which was aluminum and both picked up the machining marks left by the cherry. I might have a little contamination in the mold from sprue plate lube so I'll clean it thoroughly before any more testing. The mold was not cold. I was having to wait longer than I should for the sprue to freeze so even the sprue plate is pretty hot. The boolits were coming out frosted.

As I started casting this afternoon the mold had been pre-heated on the hot plate. I turned the hot plate up a little hotter than usual to reduce the time it took to get to temperature using alloy. After pouring about 200 boolits I had come to a conclusion that supports 243winxb's comments. I noticed upon opening the sprue plate that there was an aberration at the base of some of the boolits consistently on the side of the cavity opposite the handle end of the mold. At least I found something that was consistent. I cast faster and faster to get the mold hotter but the small spot still remained. As the casting proceeded and the head pressure diminished the spot got worse. At least it was a result I could act on. I started increasing the flow rate to the point that it was as fast as I felt I could manage without having melt go everywhere and still pile up a good puddle over each cavity. This pretty much cured the problem. I'll still clean the mold again. It's a couple of years old and has cast a few thousand boolits at this point. The circled spot on the first boolit is part of the circular flaw. On the third, fourth and fifth that is probably contamination but I didn't see that happen on today's boolits.

I forgot to try pressure casting. Will give that a shot later today and take some pictures.

I took some pictures of the mold before it go hot and was just looking at them. Even though this is a new style mold with huge vent lines I'm starting to think that Popper and Runfiverun nailed it. Some of the vents appear to be clogged with sprue plate lube. That makes sense because this is a new problem with the mold. I'll clean and test again.

David

[varmintpopper]

To Me it appears You have wrinkles near the bases on the boolits in Your pictures. either something is to cold or You are pouring to slow. And another observation is that You have a cavity in the center of some of the bases and a built up excess lead on others. Clean the mold of all oils, Add some tin to your mix, heat your mix hotter, pour faster. Just My 2
P.S., I've been casting for 62 years

Good Shooting

Lindy

[David2011]

Sorry guys, I made a newbie mistake. Literally. [smilie=b: I've only been casting for 36 years so this is a case of not paying attention to obvious problems.

Varmintpopper, yes, I have wrinkles on the sides of the boolits. The question was "why?" The variations you're seeing in the bases were related to cooling time so were of no concern to me since I knew I was the cause. Some sprues were allowed to cool until hard giving a clean cut and others were opened a little too soon resulting in minor tear out.

This is not a new mold and has made several thousand good boolits. Nothing in the process is new. I've used the furnace, the alloy involved and the mold for varying numbers of years. I just overlooked the simplest of things and confirmed it earlier tonight. The very generous vent lines in the Lee mold became clogged with sprue lube. Maybe last session before the problem appeared I was too generous with the sprue lube though it was applied with a Q-Tip as always. I'm including a picture of an older .40 cal Lee mold to compare the newer to the older venting. Image 03 shows the flaws on either side of the mold parting line. The fact that all of the flaws were on the parting line was a hint that I wasn't reading correctly.

Popper and Runfiverun had it right from the beginning. With the vents clogged the air had no place to go quickly so the melt was freezing before it could reach the mold walls even though I was pouring fast and the mold was very hot. The air could only compress so far and then the alloy quit flowing. I had varied the speed of the flow from a trickle to as cast as I could manage without seeing any significant change. I varied the concentration of tin as detailed in post 21. I varied the temperatures of the melt and the mold. Once I realized that the lube was clogging the molds I went back to the shop and cleaned the mold. I had some brake cleaner, the last of a case of the good stuff from the '90s. The sprue lube just washed away. I heated the mold with a combination of hot plate and casting and got good results.

193422 193423 193426 193425

Thanks for the contributions.
David

[Strtspdlx]

Clean the mold and cast hot and fast for a long time. My Lee molds hold onto every last trace of oil and cause havoc in appearance like what I'm seeing from yours.

[David2011]

Maybe I'll buy a good (iron or steel) mold and be done with the aggravation. Anyone that hasn't used a Lee mold doesn't know what they're missing! I know some people love 'em; I'm just not one of them.

I'll continue to use the mold and find ways to make it work for me. Maybe try some lead/tin 20:1. I'm sure that will completely change the character of the mold.

David

[robg]

One of my rcbs molds casts best if I let the stream swirl around the hole a little ,pressure casting made it worse .every mold is different .

[Oklahoma Rebel]

I love em' cause I can afford them! lol I have a noe and a lyman and they are great! I hope to get an accurate soon, I have heard nothing but good about them

[Tar Heel]

Having not read all the previous and having looked at the original photos I suggest a hotter alloy temperature and pour faster. If you have a bottom pour pot - GREAT. Increase the flow rate to fill the mold faster with a hotter alloy. Don't worry about frosting; it's cosmetic. You have to keep the temperature up to get good fills with these gang molds. Be sure the mold is CLEAN and DEGREASED. As per the instructions, smoke the mold with a match and lubricate the alignment pins and sprue cut plate with bullet lube. Just a little bit - not a lot. Wipe off excess lube with a COTTON cloth.

If you are using a dipper, get a bottom pour pot for a gang mold. Keep at it...you will solve it.

[Grmps]

I'm fairly new to casting, when I run into this problem I use the soldering torch that I use to warm the spout on the pot and basically "burn out" the affected cavities then give them a quick smoke with the butane lighter I use to light sawdust for fluxing. This almost always works. If not I use the bullets and fitz to polish the cavities for 20 seconds ea, not long enough to significantly change the size.

[David2011]

Tar Heel,

Solution was provided, not temperature related.

Thanks.

[John Boy]

* Dross in the melt - flux to remove
* Heat mold and pot melt to the temperature so with a 5 second pour, the sprue puddle frosts in 5 to 8 seconds

[Tar Heel]

Solution was provided, not temperature related.

WUHOO !! Off to the races.....

[Ficus]

I cast some Lee 357-158 flat nose boolits over the weekend and had a curious problem. The mold is a recent 6 cavity one with the enhanced vent lines. Unfortunately I can't post pictures for a couple of days. The boolits were lightly frosted and the alloy was 50/50 coww/Linotype. Yes, it's a waste of Lino IMO but my friend provides the metal for his boolits and that's what he likes.

A lot of the boolits had a circular flaw on or near the parting line on the side of the boolits near the base. The rejection rate was probably 70%. It was not in exactly the same place on any of them, eliminating defects in the cavities as the source. The noses were wrinkle free and I use a hot plate so pretty sure the mold was hot enough. I'm wondering if my pouring technique is at fault. I hold the mold at a slight angle with the handle lower than the hot end so the puddle moves toward the cavity that was poured last. I'm also wondering if the alloy might not br wetting out properly but I cast about 250 more from the same pot of alloy using a 2 cavity RCBS 9mm TC mold and the only rejects were the first and second pours. The next 250 were perfect.

I'll post pictures as soon as I get home, probably tomorrow.

192708 192709 192707

Solution found: Plugged vent line. Not temperature related as it might first appear.

David


Hi, David2011.
I'm glad you posted your experience. It led me to learn that I have a similar experience with a Lee, 6-cav .452 RNFP, my go-to bullet for 45's. I cast perhaps 1,000 of these recently and noted there were TOO MANY with large voids in the middle of one side.

I had 'prepared' the mold by spraying heavily with Frankford Arsenal mold spray and never looked at the grooves but went searching the Cast Boolit site for help. I was all ready to post a question and then saw the post about why some members will do better on the site than others. It's a gentle way of saying RTFM or in this case RTFS[tickies] or RTFA[rchives]* [*"F" in all cases stands for "Flaming"]

That's how I found y'r post and took a scan of my mold to wit:

215294

so, using a new/clean rifle cleaning brush I scraped off all the cloggy mold release agent and got this:

215295

Thank you, Y'r ol' Bud, Fike

[HangFireW8]

Fike,

That second mold pic looks a lot better.

I just got 2 new Lee molds, and they now warn against the use of spray-on mold release altogether. I think your new situation with release only in the cavities will be fine, as long as you are OK with a very slight reduction in boolit size.